05-31-2013, 10:24 AM | #1 |
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Drives: 2013 F30 335i 8SA M-Adaptive
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OBD2 Splitter/selector DIY-Use 2 OBD2 devices
So shortly after getting my 335, I needed a radar detector - so I got a valentine V1 with the SAVVY module - it plugs into the OBD2 port to get vehicle speed data then auto-mutes warnings below a user defined speed. The feature is really a sanity saver as the Valentine is sensitive and local shopping markets around my house bleed radar signals - needless to say after having the SAVVY module, it's something you'll have to pry out of my cold dead hands before I live without it.
DIY of my install of the Valentine V1, with SAVVY and a remote display are here I've also been doing a little autocrossing, and recording my sessions with TrackAddict for the iPhone - it has the ability to connect to a WiFi OBD2 reader and record RPM, Speed, Throttle position, Boost etc while taking video and GPS data on the phone and then splice them all together in a video right on the phone, or export the data for use with a program like RaceRender2. Neat stuff, so I went on eBay and picked up a $30 ELM327 WiFi OBD2 unit - worked as advertised - couldn't be happier. Example of the coolness that can be had with RaceRenderer2, TrackAddict App for iphone, and an ELM327 WiFi device Then I thought it would be nice to have access to this OBD2 data on my phone all the time, but I didn't want to give up my SAVVY - so I searched OBD2 Splitter on ebay and came up with one. It's fundamentally just a Y cable, Male on one end, with two Female pig-tails on the other end - ordered it and tried it out. It worked - kind-of - basically it seemed that the two OBD2 devices would take turns connecting - which didn't really do what I wanted. Basically device A would get data, then device B would connect kicking out device A, then device A would connect kicking out device B etc etc - not desirable. So I yanked out the splitter, plugged the SAVVY back in and slept on it. What I decided on was a selector switch - OBD2 carries power on pin 16, so if I could put a SPDT switch (single pole-double throw) on the pin 16 wire in the splitter, I could effectively select which device was being powered. I got out the exact-o knife and cut down one side of the OBD2 splitter cable. I attached one lead of a volt-meter to pin 16 on the male end, and using a really thin needle pierced the 16 wires inside cable until I found pin 16 If anybody gets one of these ebay OBD2 splitters, this is the wire color map I discovered Red 3 black 13 grey 9 purple 8 red/pink 15 orange 4 white 10 pink 11 light green 12 yellow 5 blue 7 green/white 16 Having found pin 16 was green with a white stripe, I split open the other side found the same cable, tested it was infact also pin 16 then snipped both of them - pulled the leads out of the wire, then closed up the wire with electrical tape. I then soldered some heavier gauge solid core wire onto the green/white wires, then connected the leads up to a SPDT switch I bought at autozone End result Now I had two things I wanted to do - I figured I could bury the SAVVY module inside the dash as I was happy with the 45mph mute setting and didn't need to fiddle with it, but I thought it would be nice to be able to get to the OBD2 WiFi unit - also have an easy place to plug other OBD2 things in like my E-SYS coding dongle (DIY for my dongle is here . I also wanted to hide the switch in a concealed location - the little storage cubby to the left of the steering wheel seemed ideal. I removed the cubby (two torx screws inside the cubby at the top, then use a flat-head screwdriver in the slot to push up the back of a plastic clamp that holds it to the dash from the inside - it'll just slide out then) and got to cutting. The cubby has a rubber mat in the bottom which I could use to cover up the sizable hole needed to pass an obd2 cable through, then put a little slot behind the hole for the cable to go. Once I pushed the cable through the large hole, I could reinstall the rubber mat and there would be no visible hole in the box - A picture would make this clearer I cut the hole free-hand with a Dremel rotary tool then filed the corners smooth with a hand file Then to push one end of the splitter through and mount the switch inside on the back (1/2" drill cut the hole for the switch easily) View with the Elm327 installed and switch And what it looks like from behind I also used a little obd2 extension cable with a 90 degree turn to give me some extra slack in the dash What it looks like at the OBD2 port It works perfectly and you would never know it was there, just open the cubby, reach in and "click" radar detector turns off and ELM327 WiFi turns on |
09-09-2013, 09:13 AM | #2 |
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Nicely done... I was thinking about doing something similar. Alternatively, do you see any problems with just unpluging the SAVVY OBD plug and leave it dangling in the OBD cubby, and plugging in the OBD bluetooth dongle while on the track?
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09-09-2013, 06:06 PM | #3 | |
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Drives: 2013 F30 335i 8SA M-Adaptive
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Quote:
It's just a convenience thing, and easy to flip the switch while driving if I want to look at some stat from obd while driving Also the wifi unit I have is pretty long and the port being right above the dead pedal I was afraid I was going to break off accidentally with my foot. |
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09-12-2013, 09:37 AM | #4 |
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Really done a nice job there. The display you present for us is inspiring and very professional. I am also work on it. This will be helpful for me taking ideas. thanks for this...
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